How to choose sealing paper for simple magnetizer?

Sealing paper materials are usually selected because they are very flexible and absorbent. The author also pointed out that materials with water absorption properties are easier to bond, which results in a good bond between the sealing ring paper, the voice coil frame and the cone. Only KaptonHPP and KaptonMTB skeleton materials need to be treated with high adhesion. The more general KaptonHN materials are not processed, so the lower grade polyimide skeleton made in China would be troublesome if there is no sealing paper when bonding low-adhesion materials such as PP cones.

If the sealing paper material is water-absorbing, then it cannot be compatible with the magnetic fluid, otherwise, the magnetic fluid will be sucked into the sealing paper material, which will change the useful oscillation quality and cause unstable characteristics at any time. However, good adhesion does not require strong water absorption, and a rough, non-absorbent markings can also have good adhesion. The key is to find a good sealing paper material that is compatible with magnetic fluid, which has a rough appearance and right and wrong water absorption material. Ideally non-absorbent materials should be selected such as TufQUIN from IPT.

Because the sealing paper data must be close to the two voice coil lead wires, the flexibility of the paper (softness and easy setting) is a very important characteristic. If the sealing ring paper material cannot seal the lead wire attached to the voice coil frame firmly, it may present a noise similar to a whistling sound. In addition, the loose sealing paper will supply a capillary path through which the magnetic fluid may move out of the magnetic gap. In order to prevent the magnetic fluid from moving between the lead wires of the voice coil and the sealing paper, the author suggests that the two lead wires should be glued with a sticker and then the lead wires of this length should be wrapped with sealing paper.